mtd: rawnand: Add support for manufacturer specific lock/unlock operation

Add nand_lock() & nand_unlock() for manufacturer specific lock & unlock
operation while the device supports Block Portection function.
Signed-off-by: Mason Yang <masonccyang@mxic.com.tw>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/1583220084-10890-2-git-send-email-masonccyang@mxic.com.tw

drivers/mtd/nand/raw/nand_base.c

@@ -4365,6 +4365,38 @@ static void nand_shutdown(struct mtd_info *mtd)
 	nand_suspend(mtd);
 }
 
+/**
+ * nand_lock - [MTD Interface] Lock the NAND flash
+ * @mtd: MTD device structure
+ * @ofs: offset byte address
+ * @len: number of bytes to lock (must be a multiple of block/page size)
+ */
+static int nand_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
+{
+	struct nand_chip *chip = mtd_to_nand(mtd);
+
+	if (!chip->lock_area)
+		return -ENOTSUPP;
+
+	return chip->lock_area(chip, ofs, len);
+}
+
+/**
+ * nand_unlock - [MTD Interface] Unlock the NAND flash
+ * @mtd: MTD device structure
+ * @ofs: offset byte address
+ * @len: number of bytes to unlock (must be a multiple of block/page size)
+ */
+static int nand_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
+{
+	struct nand_chip *chip = mtd_to_nand(mtd);
+
+	if (!chip->unlock_area)
+		return -ENOTSUPP;
+
+	return chip->unlock_area(chip, ofs, len);
+}
+
 /* Set default functions */
 static void nand_set_defaults(struct nand_chip *chip)
 {
@@ -5791,8 +5823,8 @@ static int nand_scan_tail(struct nand_chip *chip)
 	mtd->_read_oob = nand_read_oob;
 	mtd->_write_oob = nand_write_oob;
 	mtd->_sync = nand_sync;
-	mtd->_lock = NULL;
-	mtd->_unlock = NULL;
+	mtd->_lock = nand_lock;
+	mtd->_unlock = nand_unlock;
 	mtd->_suspend = nand_suspend;
 	mtd->_resume = nand_resume;
 	mtd->_reboot = nand_shutdown;

include/linux/mtd/rawnand.h

@@ -1077,6 +1077,8 @@ struct nand_legacy {
  * @manufacturer:	[INTERN] Contains manufacturer information
  * @manufacturer.desc:	[INTERN] Contains manufacturer's description
  * @manufacturer.priv:	[INTERN] Contains manufacturer private information
+ * @lock_area:		[REPLACEABLE] specific NAND chip lock operation
+ * @unlock_area:	[REPLACEABLE] specific NAND chip unlock operation
  */
 
 struct nand_chip {
@@ -1136,6 +1138,9 @@ struct nand_chip {
 		const struct nand_manufacturer *desc;
 		void *priv;
 	} manufacturer;
+
+	int (*lock_area)(struct nand_chip *chip, loff_t ofs, uint64_t len);
+	int (*unlock_area)(struct nand_chip *chip, loff_t ofs, uint64_t len);
 };
 
 extern const struct mtd_ooblayout_ops nand_ooblayout_sp_ops;